Relay.



A. S. GUBITT.

RELAY.

APPLICATION FILED MAY 22, 1908 'Paented June 1, 1909.

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A'RCHIBALD S1 CUBITT, OF SCHENECTADY, NEW YORK, ASSIGNOR 'lO GENERAL ELECTRIC '1 -(JOMPANY, A CORPORATIO N OF NEW YORK.

- To all whom ii racy concern:

\ RELAY.

Specificationof Letters Patent. Y

Patented June 1, 1909.

Application filed May 22, 1908. Serial No. 434,251.

' Be it known that I, ARCHIBALD S. CUBrr'r,

a subject of-the King of Great Britain, re-

siding at Schenectady, county of Schenectady, StateofNew York, have invented certain new .and useful Improvements in Re lays, of which the following is a specification.

My invention relates to relays, such as are used in connection with the control of dynamo-electric machines, and particularly to that class of relays which, under the control of a circuit in which the current varies, operate to open and close contacts in a circuit which it is desired'to control. The ordinary formsof relays used for this purpose comp "se a single current carrying coil which is connected in the circuit carrying the variable current and within which an iron core is arranged for. movement-being adapted to open and close contacts in the circuit to be controlled. After the core of such a relay has ulled u the current required to hold it in ltsraise position is much less than that re qulred to ull it u orfin other words, with a relay of t 'skin, there is a considerable difference between its raising and dropping current.

' An object of my invention is to provide and arrange alrela, which will 'pull up and drop within a sma l change of current.

, In systems of motor control in which the speed-of the motor is regulated by the amount of resistancein the motor circuit, or, if more than one motor is used, by also changing the relation of the-motors'to one another, these changes being made by a controller, .means is often provided for retarding the movement of the controller in case currentin the motor circuit rises lugher'than a certamvalue. A convenient form ofsuch retarding means consists in an 1 el e ctro magneticall operated locking de 1 vlce. for the controller, the operation of said locking device being governed by a relay, the actuating coil of which is controlled from the motor circuit. The ordinary form of relay, which after it has pulled up will not drop until the current through its actuating coil'has fallen very considerably, is unsuit-.

I produced by the able for the motor control system above mentioned, since it will keep the controller locking device in action long after the motor current has fallen below the dangerous value. My im roved form of relay is, therefore, particu arly adapted for use in connection with control systems of the above described kind since it'causes the retardation of the controller only while the current in the motor circuit is truly dangerous.

In a patent, No. 873,729, dated December 17', 1907, throttle relay, issued to my assignee, General Electric Company, and in my co-pending application, Serial No. 391,694, filed September 6, forth other forms and arrangements of relay having the same objects-"inuview as in the present case.

My invention, in the particular embodiment hereinafter described, comprises a relay having an actuating coil energized from a circuit in which the current varies, a second coil energiz d from any source and arranged to prodrce a magnetic field in opposition to and in excess of that normally actuating coil, a core of magnetic material movableQin the field of said coils, means for decreasing the magnetic effect of the second coil when said core has moved into the field and for increasing the magnetic effect of that coil when said core has moved out of said field, and contacts in the circuit to be controlled opened and closed by said core in its movement.

My invention will be clearly understood from the following description taken in conncction with the accompanying drawing, in which is illustrated one embodiment thereof.

Figure 1 shows diagrammatically a simple system of motor control having my invention embodied therein Fig. 2 is a front elevation of the relay shown in Fig. 1; and Fig. 3 is a side elevation of said relay, partly in section.

Referring to the drawing, 5 indicates the back or base of insulating material upon which the parts of the relay are mounted. The actuating coil of the relay is shown at 6 and may be of any desired number of turns of heavy conductor. A second coil 7'. of

1907, relay, I have set liner wire is shown so arranged adjacent the grammatically atA. In Fig. 1 M indicates coil l'l'ia'iiithe fields produced by the two a motor; R R and R are resistance sections will merge. The coils 6 and 7 are supadapted to be introduced into the motor cirpoi \\d in an iron U-shaped l'rame' 8 which cuit and eliminated therefrom in accelerat- T he l'astcned to the base 5 in any suitable ing; C is a motor controller of the separately 1'1l;'L:.;'l1Pl, as by screws A fixed iron core 10 actuated contact type adapted to connect may be screwed into the top of the frame 8 the motor to a source ofsup ly and regulate and iii-rain ed in pr ject downward into the the amount of resistance in t emotor circuit; coil 7, shown in 3. ll. movable core" K is a master switch governing the operation 1 1. ol magnetic material is arranged for of the motor controller; and K is an electroniovement within the actuating coil 6, as magnetic locking device for the master and projecting downwardly from this switch of any well-known form. The relay core is a rod 13 upon wl a are mounted a A has its actuating coil 6 connected in the lj-ontact disk 14 of conducting material and a motor circuit. The second coil 7 of the relay 1 cont: .t disk 15 of conducting and magnetic is connected on one side'through an inductiuateiial such as steel. The disk 14 may be ive resistance 1*, to the source, through conarrangcd as shown between collars 16 and 17 tacts closed by the master switch in all its secured to the rod 13, a spring 18 serving to on positions, and on its other side is conhold the disk yieldingl 7 against the collar 17 nected to ground through the magnetizing in a well-known manner. The disk 15 is coils 26 and 27, contacts 24 and 25, and the rnranged below a collar 19 secured to the rod disk 15, and through an auxiliary switch Z) 13, being yieldingly held in engagement with opened bythe last resistance controlling this collar by a spring 20, the tension of switchinclosing. Aresistancerisconnected which may be adjusted by a nut 21 screwing between the fixed contacts 24 and 25 and is, upon the threaded cud the rod 13. The therefore, interposed in the circuit of the coil disk 14 engages with lixed contacts 22 and 7 upon the disk 15 breaking connection with 2? of any suitable term. The disk 15 enthese contacts. The coils 6 and 7 are so gages with lixed contacls 2i and 25 of mag wound and the direction of the currents netic material which are surrounded, rethrough them is such, that the fields ro- 1W spectively, by coils 26 and 27 which are conduced by these coils oppose one anot er. nectcd in series with said contacts and when Furthermore, the field produced by the coil i2 rd serxe to produce a magnetic field 7 is, under normal values of motor current, tends to hold the steel disk 15 in enenough stronger than that produced by the gaglment with the fixed contacts 24 and 25 coil 6, when the resistance r is short-cirduring the greater part ol' the upward movecuited by engagement of the disk 15 with the ment the core in a manner well-known to contacts 24 and 25, to roduce a resultant those familiar with this art. The arrangemagnetic field which will cause the core of merit of the collars l7 and 19 is such that the relay to rise. The core in rising will lift when t ne core of the relay is down it will be the disk 15 and cut the resistance r in cirigenient ol the disk 15 cuit with the coil 7, thereby decreasing the cooperating fixed contacts, while strength of the ma netie field produced by isli 1l will be pressed against its cothis coil but not su iciently to cause the core ing .ontacts by the spring 18, thereby of the-relay. todrop. The core of the relay lsuringgood electrical connections between will drop onl T when the current in the motor the and the fixed contacts. The mecircuit rlsesto such a value that the fieldprochanieal construction of the relay is very duced by the coil 6 in 0 position to that'pr'osimilar to that of the relay shown in my duced by the coil 7 will reduce the resultant Patent No. 973,729, r :lerrcd to, and confield in strength below that required to hold tains no mechanical features not well-known the core of the relay up. By adjusting the to those familiar with this art. The elecvalue of the resistance r the motor current at trical arrangement of therelayand its relation which the relay will drop can be easily reguto the circuit which controls it and the cirlated. The contacts 22 and 23 are concuit which it controls are, however, new as nected in circuit with the actuating coil 7c of will now be pointed out in a description of the locking mechanism on the master switch, its mode operation when incorporated in and when the core of the relay is down the the ern ol' control illustrated diagramdisk 14 com letes the circuit through the 1 l il. actuating coil lc and operates the locking de- Inn shown in Fig. 1 is of the zepavice. Upon closing of the last resistance ratcly-actuated contact type in which the controlling switch the auxiliary switch Z is r star switch is provided with a locking deopened and the circuit through the coil 7 of vice which will restrain it from further movethe relay is 'interru ted, thereby preventing It at any time the current in the motor waste of current in t is coil. circuit exceeds a certain value, the operation From the foregoing description it is clear of this locking device being controlled by the 'that the master switch K will, in its firs relay herembelore described and shown diaposition, cause the motor to be connected to line through all the resistance, R R and 3 and that the successive points on the master switch-provide for operation of the might at once pull up,

,first position.

through the coil? sufiicientl'y to allow the current in the motor circuit through he coil 6 to build up and hold the core o'f'the relay in its lower position if the motor current reaches the value at which this relay is designed to operate. In this way the master switchis prevented from being moved through its first 'ew positions without being subject to the control of the locking device. When the current in the coil 7 has risen to its maximum value and the current in the motor ciruntil the current drops and the cuit through thecoil 6 has dropped to a safe value, the relay pulls up and opens the circuit through the coil is of the locking device, thereby causing the latter to release the master switch and ermit its forward niovemerit. If during tie further movement of the master switch the current in the motor circuit exceeds the safe value, the relay A controller locking device-prevents iurther movement of the master switch in the motor circuit has iallen sufficiently to allow the relay A topull up again. The resistance r can, if desired, be made of such a value that its insertion in and removal from the circuit of the coil 7 will kee constant the pull exerted by the magnetism of the coil7 upon the core 11 as the air gap is varied between this core and the fixedcore 10. In this way the relay may be made to operate within a small change ol current in the operating circuit.

What I claim as new and desire to secure by Letters Patent of the United States is,-

1. In combination, an electrical circuit in which the current varies, a circuit to be controlled, a relay com rising an actuating coil energized from sai' first named circuit, a second coil arranged to produce a magnetic field in opposition to and in excess of that normally produced by said actuating coil, a core movable in the field of said coils, means for decreasing the magnetic effect of the sec ond mentioned coil when said core has moved into the field and for increasing the magnetic effect of said coil when said. core has moved out of said field, and contacts in the circuit to be controlled opened and closed by said core in its movement.

2. In combination motor circuit which the current varies, a circuit to be con trolled, a relay comprising an actuating coil energized from said first named circuit, a sec ond coil arranged to produce a magnetic field in opposition to and in excess of that normally produced by said actuating coil, a core movable in the fields of said coils and biased for movement out of said field, means for automatically increasing the magnetic effect of the second mentioned coil after said core has moved out of the field and decreasing its magnetic effect after said core has moved into the field, and contacts in the circuit to be controlled by said core in its movement.

3. In combination, an electrical circuit in which the current varies, a circuit to be controlled, a relay comprising an actuating coil energized from said first named circuit, a second coil arranged to produce a magnetic field in opposition to and in exccss of that normally produced by said actuating coil, a core movable in the fields of said coils and biased for movement-out of said field, contacts controlled by said core arranged to interpose a resistance in the circuit of the second mentioned coil when said core has moved into the magnetic field and to remove said resistance from the circuit when said core has moved out of the field, and contacts in the circuit to be controlled opened and closed by said core in its movement.

4. In combination, an electrical circuit in 1 which the current varies, a circuit to be coninto the field by said second mentioned coil,

contacts controlled by said core in its move ment arranged to interpose a resistance in circuit with said second mentioned coil after the core. has moved into the field and to remove said resistance from the circuit after the core has moved out of the field due tot-he increase in current in said actuating coil, and contacts in the circuit to be controlled opened and closedby said core in its movement.

In a'motor control system, a motor, a sourceof current, supply, a starting rcsistance, a controller for connecting said motor to said source and controlling the amount of resistance in the motor circuit, a relay com prising an actuatingcoil. energized from the a second coil arranged to produce a magnetic field in opposition to and in s cooperating with said controller for connecting said second mentioned coil to the source an electrical circuit in through said inductive resistance in the on p'ositimm of H10 mr-nimlivr. n100mofi'nmgnvt'ic malarial movable in Hm Holds of mid mils, 111mm I'm dvwmsing' U11 mngnvtiv (-Hwt of H10 sm-oml mun! immi mil hon said (011* has char mcration of said lwking; device. 1G in \vltness .vhorsoi, 1' 11mm hereunto set my hum! this 20th day of Mmv, 1908.

mats (rolmmlkd by said relay for conm'olfing 

